LTspice/SwitcherCAD III explanation

The IC supplier Linear technology provides his own circuit simulation package called LTspice/SwitcherCAD III
Although the main intention is to ease the design process of Linear's customers, the software is freely available to all and it is a general purpose analog simulator.

My addition: Pulse Width Modulation source

This is a controlled voltage source which produces the Pulse Width Modulated version of any signal.

A screenshot, click to enlargeThe voltage source is a so called arbitrary behavioral voltage source which is set up with a special mathematical expression.

Note that the Control library also contains two convenient PWM modulator building blocks. One of them has complementary outputs and a deadtime parameter.

My addition: Control library for use with LTSpice/SwitcherCadIII

This is an addition to the circuit simulation package LTSpice/SwitcherCadIII, which gives convenient access to a set of blocks such as PID regulators, 1st order phase lag system, multiplier, PWM modulators, etc.

Some examples with screenshots and the LTspice schematic files

Click the images for large view, for each example the schematic file is linked.
You need the control library and symbol files to use these examples, see the download section.

How to use the control library:

To use this the library (text file) control.lib must be placed in the directory:.\LTC\SwCADIII\lib\sub
The symbol files contained in control.zip must be placed in the directory:.\LTC\SwCADIII\lib\sym\control
(best in the new to be added directory control, so these new blocks do not mix up with the regular components).
Then the symbols are available to be selected amongst the regular components.

It is best to turn 'Skip initial operating point solution' option ON when doing transient simulation.
Find these files in the download section

My addition: Cosmetic symbols for use with LTSpice/SwitcherCadIII

These symbols can be used for illustrative schematics, they do not have models linked to them yet. However they can be used for simulations if a suitable model is provided.

Silicon Controlled Rectifier SCR

Using a generic model taken from:
http://pages.suddenlink.net/wa5bdu/ltguide.pdf
These examples of controlled half wave rectification can be made, the SCR model file is included in the schematic. The pin order had to be changed to match the SCR symbol that comes with LTSpice.